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Supplementary feeding of birds may have considerable ecological and evolutionary effects on bird communities. However, there is a lack of basic information on the prevalence, frequency and quality ...

Little is known about the seasonal elevational movements for most tropical avifauna species. Seasonal elevational movements of the Eastern Olive Sunbird Cyanomitra olivacea were studied along an elevational gradient from 600 to 1 500 m above sea level in the Uluguru Mountains, Tanzania, between May 2005 and February 2006. The recapture of ringed individuals along an elevational gradient across seasons provided evidence for the seasonal elevational movement of the Eastern Olive Sunbird in the Uluguru Mountains and the first documented evidence for this species in the Eastern Arc Mountains as a whole. Due to forest fragmentation and lack of corridors connecting high- and low-altitude forests in the Uluguru Mountains, the results have implications for conservation of the forest along the entire elevational gradient as well as for other forest bird species that have been documented to make seasonal elevational movements in the Uluguru Mountains and the entire Eastern Arc Mountains.

Sunbirds usually perch when visiting flowers for nectar and only rarely hover. Except for three studies of sunbirds visiting introduced plants in South Africa and India as well as a native plant in Cameroon, there have been no quantitative studies of sunbird hovering behaviour. Here I present detailed observations of foraging behaviour in two sunbird species (Malachite Sunbird Nectarinia famosa and Southern Double-collared Sunbird Cinnyris chalybeus) at flowers of three Salvia species (Salvia africana-lutea, S. lanceolata and S. africana-caerulea; Lamiaceae) and one natural hybrid as well as Lycium afrum (Solanaceae) in South Africa. The birds not only perched, but also hovered (up to 28% of total visits) and sometimes hover-clasped (up to 3%). Other birds only rarely (Karoo Prinia Prinia maculosa) or never hovered during flower visits. These observations indicate that the foraging behaviour of specialist passerine nectarivorous birds overlaps with that of hummingbirds more than was previously thought.

We measured δ13C and δ15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in δ13C and δ15N isotope values of flight feathers (range = 3.1%o and 2.7%o, respectively) indicated that the source of carbon (i.e. C3 or CAM) and trophic level position shifted significantly during the flight feather moult period. Temporal dietary changes in an individual sunbird highlight the implications for interpreting avian diets using stable isotopes. However, by analysing feathers, dietary input may be interpreted at different levels if the moult process is well understood.

Summary Craig, A.J.F.K. & Hulley, P.E. 1994. Sunbird movements: a review, with possible models. Ostrich 65: 106–110. Based on current fieldwork, we propose four possible models to explain the winter influx of sunbirds which we have observed: the birds may be (1) “winter residents”, which move annually to a wintering area and remain there; (2) “shoppers”, which periodically investigate feeding areas within their home range and feed opportunistically where nectar is most abundant; (3) “tourists”, which successively visit a series of sites on a regular itinerary; (4) “nomads”, which move unpredictably to new areas whenever food supplies decline. and have no home base. Current data on sunbird movements are reviewed, and in a few cases the winter resident model is unlikely, but generally it is not yet possible to eliminate any of the hypotheses. Moult cycles based on both field and museum studies may provide additional information, as movements are unlikely while active wing-moult is in progress; some species ...

Summary Earle, R. A. 1982. Aspects of the breeding biology and ecology of the Whitebellied Sunbird. Ostrich 53:65-73. Breeding of the Whitebellied Sunbird Nectarinia talatala near Pietermaritzburg was recorded during six months of the year although males were capable of breeding for at least eight months. The same nest site was often used in consecutive years but the same nest was never used twice. 80,4 % of the nests built were between 0,6 and 1,s m off the ground. Nests built in thorny shrubs were the most successful but the highest percentage of nests were built in Prickly Pears Opuntia spp., which was probably an anti-predator device. Two colour-types of eggs were laid but the same female was always found to lay only one type. The greater majority of clutches consisted of two eggs (82,7%) but one and three egg clutches also occurred. Incubation started either after the first egg of a clutch was laid (64%) or after the second egg (36%). One case of double-broodedness was recorded. Incubating females mo...

Summary Hanmer, D. B. 1981. Mensural and moult data of nine species of sunbird from Mocambique and Malaŵi. Ostrich 52: 156–178. Wing length, culmen length, weight and moult data are given for the Coppery Sunbird Nectarinia cuprea, Purplebanded Sunbird N. bifnsclata, Yellowbellied Sunbird N. venusta, Whitebellied Sunbird N. talatala. Grey Sunbird N. veroxii, Black Sunbird N. amethystina. Scarletchested Sunbird N. senegalensis. Collared Sunbird Anthreptes collaris and Violet-backed Sunbird A. longuemarei from Mopeia (Mocambique) and Nchalo (Malaŵi). Moulting seasons, immature age at moult, the duration of primary moult, its relation to the breeding season, weight changes with moult, the breeding season, altitude and latitude, and the sequence and timing of moult in remiges and rectrices are discussed for all species except N. veroxii, N. amethystina and A. longuemarei. Softpart and plumage colour changes with age are discussed and some data are given on habits and migration.